The Impact of Monthly Prophylactic Antibiotics Use in Patients with Recurrent Cellulitis: A 20-Year Population-Based Cohort Study in a Medical Center

PURPOSE: The vicious cycle of recurrent cellulitis ultimately results in a high risk of relapse, which facilitates the use of antibiotic prophylaxis with monthly intramuscular benzathine penicillin G (BPG) to prevent recurrence. However, several clinical situations hinder the guideline recommendations in daily practice. Therefore, intramuscular clindamycin has been used as an alternative in our institution for years. This study aims to elucidate the effectiveness of monthly intramuscular antibiotics in preventing further cellulitis recurrence and evaluate the applicability of intramuscular clindamycin as an alternative to BPG. PATIENTS AND METHODS: A retrospective cohort study was conducted at a medical center in Taiwan from January 2000 to October 2020. Adult patients with recurrent cellulitis were enrolled to receive monthly intramuscular antibiotic prophylaxis (including 1.2–2.4MU BPG or 300–600mg intramuscular clindamycin) or to be observed without prophylaxis. The decision to administer prophylaxis or observe was made at the discretion of the examining infectious disease specialists. Cox proportional-hazards regressions were performed to estimate hazard ratios (HR) and adjust for variables between groups. The Kaplan–Meier method was used to estimate survival curves. RESULTS: Enrollment in the study consisted of 426 patients, with 222 receiving BPG, 106 receiving intramuscular clindamycin, and 98 being observed without prophylaxis. Both types of antibiotics resulted in a significantly lower recurrence rate than observation alone (27.9% for BPG, 32.1% for intramuscular clindamycin, and 82.7% for observation, P < 0.001). After adjusting for multiple variables, antibiotic prophylaxis continued to significantly reduce the risk of cellulitis recurrence by 82% (HR 0.18, 95% CI 0.13 to 0.26), by 86% (HR 0.14, 95% CI 0.09 to 0.20) with BPG, and by 77% (HR 0.23, 95% CI 0.14 to 0.38) with intramuscular clindamycin. CONCLUSION: Monthly intramuscular antibiotic prophylaxis was demonstrated to be effective in reducing cellulitis recurrence. Moreover, in the real-world practice, intramuscular clindamycin may serve as a reasonable alternative option to BPG.